The distant galaxy that might have revealed the universe's first stars

Space · Published 18 October 2026 Swipe more like this →

In short: At a redshift of 6.6, Cosmos Redshift 7 allows us to peer back to just 800 million years after the Big Bang. While it was once thought to hold the secrets of the universe's very first stars, recent findings have complicated this cosmic discovery.

Cosmos Redshift 7, also known as CR7, is a high-redshift Lyman-alpha emitter galaxy that serves as a window into the epoch of reionisation. When astronomers observe CR7, they are seeing light that has traveled for 12.9 billion years. This extreme distance makes it one of the most ancient and distant galaxies known to science.

Using a vast array of tools, such as the Hubble Space Telescope, the Subaru Telescope, the W. M. Keck Observatory, and the European Southern Observatory's Very Large Telescope (VLT), David Sobral from Lancaster University headed the finding. M. Keck Observatory. At the time of its discovery, CR7 was notable for its immense luminosity, appearing three times brighter than the brightest galaxies found at redshifts greater than 6.

CR7 previously stood as a leading prospect for containing Population III stars, which represent the initial stellar generation born throughout early galactic development. Extremely low metallicity defines these particular stars. While a bright pocket of blue stars in CR7 initially showed expected signatures of this first generation, recent studies have found no evidence for Population II stars in the galaxy. The galaxy is known to contain older, metal-poor Population II stars, but the presence of the elusive Population III remains unconfirmed.

Interestingly, the galaxy's name carries a terrestrial connection: the designation 'Cosmos Redshift 7 Galaxy' was inspired by the famous football player Cristiano Ronaldo, widely known as CR7.

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